Could deep sea microbes help fight climate change?

By Erin Blakemore

Special to The Washington Post

Victoria Orphan has a problem. The geobiologist wants to understand how tiny microorganisms interact with their physical environment. But the organisms she wants to study aren’t exactly easy to access: they live on the very bottom of the ocean floor. Orphan’s quest to study those elusive microbes has taken her deep into one of Earth’s last frontiers — and her latest frontier is life as a MacArthur grant winner.

There are compelling reasons for studying archaea and bacteria at the bottom of the sea. Both organisms play a fundamental role in gobbling up methane, a greenhouse gas that gets trapped at the bottom of the ocean in the form of an icelike solid substance. Those substances, called methane hydrates, dissolve when ocean pressure or temperature changes. Given the expected effects of climate change on ocean temperature, large amounts of trapped methane could one day make their way into the atmosphere, warming it even more.

If Orphan, a professor of Environmental Science and Geobiology at the California Institute of Technology, can figure out what makes these deep sea microorganisms tick, she could help make climate models more accurate. But the organisms aren’t exactly easy to study in a lab. Not only are they located deep beneath the sea, but they’re hard to take to the surface. Their deep sea habitat is quite cold and high in pressure, and by taking microbes to the surface Orphan risks destabilizing them. So she’s developed a number of creative ways to learn from them without ruining them.

Sometimes she studies them on the seafloor with the help of submarines; sometimes she collects them with robotic submersibles. She’s learned to study the microbes individually and collectively, tracking their chemical signatures as they make their way through the food chain. What she can bring back to the lab must be stored and worked with in carefully controlled conditions. “We’ve learned over time to at least keep them going in the lab,” she said. “We create our own sort of artificial methane sea world. It’s not glamorous.” Think: refrigerators, gases and tubes that help keep the organisms from freaking out.

How exactly do those microbes sequester all of that methane? Orphan isn’t sure yet. “We can ignore them because they’re doing their job,” said Orphan. “But if you want to do forecasting of how they might mitigate greenhouse gases in the future, we really need a good baseline.” With each cruise, submarine trip and robot mission, her team gets closer to understanding the relationships those methane-metabolizing microbes have with one another and the environment around them.

By slowly figuring out how deep sea microbes oxidize methane, Orphan isn’t just helping scientists predict what’s up with greenhouse gases. She’s also making unexpected discoveries. “Every time we go to one of these environments, we discover totally new forms of life,” she explains. The newly discovered species her team encounters under the oceans look otherworldly and even freaky — like the yeti crab, a hairy, crustacean covered with shaggy filaments of bacteria. And Orphan also contributes to medicine, too, collaborating with her fellow MacArthur fellow Dianne Newman on work that could use anaerobic bacteria to fight conditions, such as cystic fibrosis.

For Orphan, who hopes to use her $625,000 grant to take on “risky science endeavors,” it all comes full circle when she looks at the ocean. “Most of the Earth is ocean,” she explained. “It’s hard to get across how under-explored the oceans are and how important microbial life in the oceans is.”